It is known in the telematics services industry to have vehicles communicate through wireless transceivers (such as cellular telephones) embedded in vehicles and through wireless transceivers that are portable hand-held devices. Portable devices are interfaced with the vehicle either through hardware links such as a cradle in the vehicle or through short-range wireless links of the type used in wireless networking. Short range wireless links typically use very low power, operate at upper megahertz or in the gigahertz frequencies, and have the ability to communicate a limited range, for example 30 to 90 feet (or more depending upon local regulations and/or the standard implemented).
Portable hand-held transceivers, such as analog or digital cellular phones, typically have a power-off state, where all functions are disabled, and a power-on state, where functions are enabled. When in the power-on state, the device may be in a power conservation mode, which conserves energy, but still allows initiation of receipt and transmission of calls.